Several years back a AUSA (Asst, U.S. Atty.) and I had some time to kill before court and we began discussing firearms. He was quite knowledgable about handguns, and of course knew a lot about the law, too. His advice on home defense and CCW was to use the same caliber as your local law enforcement did. He also recommended that whatever gun you chose in that caliber be kept stock, with minor, non-cosmetic changes to be okay. In his experience, non-standard rounds for exotic calibers and hot shot bullet's fired from tricked out guns, were an excellent way to lose a lawsuit. In his opinion, even if not prosecuted on criminal charges, a civil lawyer will tear you to shreds for spending "thousands of dollars to make this killer's weapon, a regular gun was not lethal enough." But stock guns and law enforcement ammunition are easily defensible.